Process of desulphurizing iron and steel and a composition of matter for use in said process



' Patented Aug. 11-, 1925.

UNITED STATE-S,

PATENT oilce.

I DANIEL nmoxsoit, or nnooxmm, unw'yonx, .rosnrn n. sums, or nnoomrmnn,

AND FREDERICK CO'NLIN; F WESTFIELD, NEWRTERSEY, ASSIGNORS TO SAID JACK- SON, SAID SEARS, AND JOHN T. PRATT, OF NEW YORK, N. Y., AS JOINT TRUSTEES.

' successor .nnsunrmimzme men AND swam; AND A oomrosrrrou OF'IlEATTER non; use IN sun rnocnss.

To all whom,- z't-may concern: I

Application filed February 22, 1922. Serial m. 538,423.

Be it known that we, -DANIEL D. J ACKSON, residingin the-borough of Brooklyn, city and State of New York, JosErH D. SEARS, residing in 'Bloomfield, 'county of Essex, and State .of New Jersey, and FREDERICK CONL'IN, residing in Westfield,- county of Union, State of New Jersey, citizens of the United States of America, have invented certain nwQ-and useful Improvements in Processes of -Desulphurizing Iron and Steel and a Composition of Matter for Use in Said Processes, of which the following isa specification. A r

This invention relates to a process of treating iron, steel, ferro-alloys-and copper, for re ucing or eliminating the sulphur content thereof, and to a composition of matter for use in such process, andaims to provide improvements therein.

y The inventionprovides an improved and. highly effective process of reducing or eliminating the sulphur content in iron, steel, ferro-alloys and copper. It further provides a process which is very simply and readily carried out in' connection. with present operating equipment in general use for producing'iron, steel, etc.

. The invention further provides a process using a class of reagents which are in abundant-supply in the market. I

The invention further provides a composition of matter, which is useful in the above.- mentioned process and which may be put u'pin a form convenient for useand safe for handling.

- V A specifioapplication of the process and a form in whichthe composition of matter may be embodied are illustrated in Figures 1 and 2 respeotivelyof the accompanying drawing. f According to our discovery and researches, sulphur, found as an impurity in iron, steel,

1 etc., can be virtually eliminated, or its content iniiron, steel, etc., substantially reduced by treating the molten metal containing the sulphur, with certain mixtures of alkali- -metal comp'ounds,which unite or combine with the sulphur compound of the iron. A

been found to give good results in reducing the sulphur contentof iron and steel.

-Among these substances may be mentioned sodium hydroxid, sodium carbonate, potassium carbonate, potassium hydroxid, and sodium or potassium silicate together with one or more of the preceding.

Our researches and discoveries have also shown that the sodium compounds, in combination with sodium silicate, give a decidedly superior desulphurizing action.

Our researches and discoveries have also shown that mixtures. of alkali-metal hydroxids and carbonates indiscriminately with other substanoes, instances of which are found in prior art patents, do" not have an action which can be regarded as of significant or technical importance.

It is not intended to beintlicated herein, however, that the alkali-metal compounds, or. their mixtures with alkali-metal sllicates,

asset forthherein, may not be used to- 'gether with other substances which do not destroy or materially disadvantageously affeet the desulphurizing .action of said reagents. Using sodium hydroxld as the reagent,

would probably be- The alkali-metal reagent is brought into 4 the reaction upon the sulphur in the metal v contact with the molten iron, steel, etc. in

any suitable or known manner practiced in metallurgy, but is conveniently placed or dumped-onto the surface bf the metal con- I tained in an ordinary ladle, crucible, converter, hearth, or the like. Any overlying slag, so far as possible, is removed from the surface of the molten metalf A-complete covering of the surface of ,the" metal with the desulphurizing material will give the greatest efficiency. The heat of the metal "will dissociate the sodium hydro-xid, which will breakup into-sodium oxid and water vapor which will be evolved. The. sodium hydroxid will bemelted to afluid consisan alkali-metal silicate.

5 the mass into contact with the liquid layer of the sodium hydroxid onthe surface thereof, thereby reacting with the sodium oxid to form sodium sulphide, and probably some one or more oxy-sulphur sodium compounds, which enter therslag produced by the treatment.

In the drawing, Fig. 1 the molten metal (designated by reference letter A) is illustrated as being contained in a ladle B. G designates the surface layer of liquid sodium hydroxid.

In experiments on iron, using'a mixture of sodium hydroxid and sodium carbonate (equal parts) as the desulphurizing reagent, spread out as a liquid la er on the surface of the molten iron, a re uction as high as 67% of the sulphur contained in the iron has been obtained,at a single treatment, via, a reduction from 146% S. to 048% S.

3 It has been further discovered that a bet; ter result in reducing the sulphur content of iron, steel, etc.,' by the use of the reagents hereinbefore mentioned, may be obtained by' using said reagents concurrently with reagent and the alkali-metal silicate .are conveniently mixed, and the mixture used in 'the same manner'as the use of the alkalimetalreagent has been described. For convenience in handling, the two or mixed reagents are preferably fused into cakes of a regular 'size, and for comfort and safety in handlin where one of the ingredients may be caustlc, and for preserving the condition 40 of the mixture where oneof the ingredients may be hygroscopic, the mixture may be covered 1n any suitable manner, as by a box,

'. or by-a coating of parafline.

In the drawing, Fig. 2, which illustrates a form of the com osition of matter comprising the alkali-metal reagent and theal.-

ali-metal silicate, the letter M designates a cake conslstmg of a fused mixture of said 4 ingredients, and Q designates a coating or paraifine wax covering said cake.

With a mixture of sodium h droxid' and sodlum silicate (solid water g ass) spread out as a liquid-layer on the surface of the molten metal, the sulphur content of iron has been reduced as much as 97% at a single treatment, yi'z, a reduction from ;114% S. to 004% S. Amixture of from 85-95% sodium hydroxid to from 545% sodium 811163136 has 'ven best results in use,

the highest reduction of sulphur having ture ofsOdiumparbonate, and sodium sili- The alkali-metal cate spread out as a liquid layer on the surface of the moltenmetal, the sul hur content of the-iron has been reduc as much. as 68% at a single treatment, viz, a reduction from 158% S. to 05% S. In experiments upon iron, using a mixture of sodium liydroxid, sodium carbonate, and sodium silicate in the proportions of 90% sodium hydroxi'd, and sodium carbonate, and 10% sodium silicate, as the desulphurizing reagent spread out as a liquid layer on the surface of. the molten iron, a reduction as highas' has been a single treatment.

With a mixture of sodium hydroxid (90%) and sodium silicate (10%) used on copper (Lake copper) the sulphur content has been reduced as much as 91% at a single treatment, viz, a reduction from .117 S.

Usually from '10to 25 pounds of this mixobtained, at

ture to a ton of iron is used, depending on the sulphur content and the amount of sulphur desired to be removed. .Where the carbonate is used in the place of the hydroxid, or where potassium is used in the place of sodium, the amount to be used may be calculated'on the basis of the Na,() content of the sadium hydroxid.

Gorrespondin" results in foundry practice have been (itained by using the abovementioned reagents and mixtures thereof with silicates (water glass).

The alkali-metal silicate when used alone will act" to reduce the sulphur content of iron, steel, etc., but this per cent. of reduc tion is small 'as compared with sodium-hydroxid and sodium carbonate, showing about a 14% reduction.

The conjoint use of the alkali-metal silicate (Water glass) with another alkalimetal reagent such as sodium hydroxid or carbonate, in the proportions previously.

designated, givesthe best results, as the sulphur reduction in such case issuperior to that obtained by any of the alkali-metal reagents alone. v 1 The mixture of alkali-metal hydroxid' and alkali-metal carbonate is less volatile when heated on the molten bath than hydroxid alone, produces a less watery layer or sla on the surface of the metal than hydroxid alone, and melts more quickly than carbon-- ate alone. mainly as a' binder of the other ingredient or ingredients of themixture and to thereby The alkali-metal silicate is used promote the quick meltin of the mixture. g It is to be understood t at the carbonate 7 beside reducing the volatility of the hy-' droxid, has other beneficial roperties such asfreducing the 'tendency'o the hydroxid to act on the silicon. in the iron, and that the silicate also has other pro rties, such as reducing the volatility of t e hydroxid.

.Where the {alkali metalreagent, either alone or associated with analkali-metal silicate, is used with other substances which to a thin or urizing action fluid consistency, the desulp mferior to what has been found to be much I it is when the reagent at a thin or fluid consistency.

The process may be carried out by various other procedures than that specifically de-- scribed.

Claims to the mixture of sodium hydroxid and sodium carbonate, and to the fused mixture thereof, and to the process of desulphurizing with this mixture, are contained in our copending application Serial No. 631,925, filed April 13, 1923.

What is claimed'is:-

1. A process of treating iron, steel, ferroalloys, and copper for diminishin .or eliminating the sulphur content thereo comprising treating the molten metal with a mixture of alkali-metal hydroxid and alkalimetal carbonate, the carbonate being present in an amount to reduce the volatilization of the hydroxid.

2. A rocess according to claim 1 in which an alka i-metal silicate is contained in the mixture of hydroxid and carbonate, the silicate binding the other ingredients of the mixture prior to melting. a

3. A process of treating iron, steel,ferro alloys, and copper for diminishin or eliminating the sulphur content thereo comprising treating the molten metal with a mixture of an alkali-metal silicate, and at least one of the following: alkali-metal hydroxi-d, alkali-metal carbonate; said silicate binding the other ingredients of the mixture prior to melting. v

4. A process according to claim 3, further characterizeddiy the silicate being present in the proportion of 515% and the alkalimetal hydroxid, or carbonate, or mixture of hydroxid and carbonate, from 85-95%.

5'. Aprocess according to claim 3, further characterized by the silicate being present inthe proportion of substantially 10%, and

the alkali-metal hydroxid, or carbonate, or mixtur of hydroxid and carbonate, 90%.

6. A process according to claim 1, further the lngredlents being presulphurizing iron, steel, ferro-alloys, and copper, consisting of alkali-metal hydroxid and I alkali-metal carbonate, the carbonate being resent in an amount to reduce the volatillzation of the hydroxid at the temperatures of molten metal.

9. A composition of matter for use in desulphurizing iron, steel, ferro-alloys, and copper, consisting of an alkali-metal silicate and at least one of the following: alkalimetal hydroxid, alkali-metal carbonate, the silicate binding the other ingredients of the mixture. I

10. A composition of matter according to claim 9, further characterized by the alkalimetal silicate being representatively in the proportion of 5 to 15% and the alkali-metal hydroxid, or carbonate, or mixture, from 85 to 95%.

'11. A composition of matter according to claim 9, further characterized by the alkalimetal silicate being substantially in the prosigned our names.

DANIEL D. JACKSON. J OSEPHD SEARS. FREDERICK CONLIN. 

